Composition for su percarbu rizing steelvbgc



' clude oxygen from the heated metal, and

- llNr-rEn Suffix"rfns PATENT OFFIC HAYWARD A.-HARVEY, 0E ORANGE, NEW JERSEY, ASSIGNOR TO T'HE'HARV'EY STEEL COMPANY, or NEW YORK, N. Y., AND NEWARK, NEW JERSEY.

COMPOSITION FOR SUPERQARBURIZING STEEL, sec.

SPECIFICATION forming part of Letters Patent No. 498,390, dated May 30, 1893 Application filed January 28. 1893. Serial No..460,155I (No specimens.) p I V I To all whom it may concern.- 7

Be it known that I, HAYWARD A; HARVEY, of Orange, New J ersey,have invented a cer tain Improvement in Compositions for Supercarburizing Steel During the Subjection of the Same to High Temperatures, of which the following is a specification.

This improvement relatesto the composition of the body of carbonaceous material employed for supercarburizing steel in the process of treating low steel, described in United States Letters Patent No. 376,194, is-

sued to Hayward A. Harvey January 10, 1888, and also during the process of manufacturing decrementally hardened armor plate, .described in United States Letters Patent No. 460,262, issued to Hayward .A. Harvey September 29,1891. In. said processes, inwhich the steel under treatment is subjected to intense heat, it is essential to completely excharcoal in the form of .fine powder is the best material for the carbonaceous body.

Several objections have heretofore been experienced in such use of finely powdered charcoal. It has been found necessaryto deeply embed in the powdered charcoal, the metal to be treated because of the tendency of masses of powdered charcoal to subsidence when heated. This has involved the employ ment of treatingchambers of undesirably large vertical dimensions and corresponding increase in the height of the furnace chambers. Another difficulty has arisen from the tendency of the finely powdered charcoal to fly off in dust when stirred or moved from place to place as it has to be when loading and unloading the treating-chamber. It is also the fact that for some reason, the nature of which is not fully understood, when fine Wood charcoal alone is used and is subjected to high heat, explosions occasionally occur. These explosions are forcible enough to blow off the cover of a closed receptacle, orif the receptacle containing the fine charcoal is not I closed and the charcoal is covered with a layer of sand and a superposed layer of fire brick, as described in Letters Patent of the v United States No. 460,262, a species of ebullitionis observed to take place in the granu- 5o .lar mass by which the mass is loosened so as to diminish the firmness of its compression aga nst the steel which is to e supercarbu- I'lZBdb These difficulties are practically overcome byfthe present invention which consistsin forming the carbonaceous body, which for present convenience may be called the treating bed, partly of finely powdered wood charcoal and partly of animal charcoal, preferably the so-called spent char, from sugar I refineries.

The specific gravity'of animal charcoal 1s nearly four timesthat of wood charcoal, and it is found that the presence of the animal charcoal lessens the extent 0f subsidence of the compressed massof carbonaceous material when heated, 'diminishes the. tendency of the finely powderedwood charcoal to fly off in dust whent'he mixture is handled either in the act of filling the chamber in which the heating opera-' 7 0 tion isc'arried on, or in the act of emptying the said chamber preparatory to, or in connection with, the removal of the metal from the treating bed, and prevents the occur- I tion in the quantity of dust arising. under the circumstances referred to, and forty to fifty per cent. almost entirely prevents the escape of dust. The finely powdered vWood charcoal occupies the interstices betw een the particles of animal charcoal. During the handling of the mixture the animal charcoal acts as a carrier for the finely powdered wood charcoal, and also acts as ashield, which to a greater or less extent prevents the finely powdered wood charcoal, or charcoal dust go from escaping into the. atmosphere. Owing to the inclusion in it of animal charcoal, the material-of the treating bed is valuablefor manufacture intofertilizers, for which purpose it can be readily sold after repeated use 5 has caused it to part with its carbon to such an extent as to impair its efieetiveness for the purposes herein mentioned.

What is claimed as the invention is The herein described treating bed for elfect- 5 ing the snpercarbnrization of steel during the subjection of the same to high temperature, the same consisting of a mixture of finely powdered wood charcoal with animal charcoal, as and for the purposes set forth.

HAY WARD A. HARVEY.

\Vitnesses:

E. GATTERER, A. M. J ONES. 

